Thermoforming, of course, is a well-established process for packaging and technical parts. But the use of engineering thermoplastics (etp) in technical-part thermoforming has lagged, largely because materials suppliers have not pursued such lower-volume applications as aggressively as high-volume injection molded ones.
That is changing, say officials at GE Plastics, Pittsfield, ma. The company is turning attention and assets on the process, including introducing materials into markets where neither etps nor thermoforming have seen wide use.
In the last two years, GEP has worked with U.S. processors to validate its sheet-extrudable materials for thermoforming. “Now, we’re ready to launch this on a much bigger scale,” says Christine Murner, market development manager for emerging markets.
Reasons for the heightened emphasis abound. But one of the drivers is that the company’s new president and ceo, Yoshiaki Fujimori, is pushing management to target potential and growth markets, in light of recognizing that areas where the supplier has long been strong — such as polycarbonate — are realizing lower margins due to increased supplier competition and material capacity.
Thermoplastics are now widely accepted in automotive body panel moldings, notes Dan Sowle, technical manager for emerging markets. “Even 10 years ago, this wasn’t the case,” he says. But Sowle says injection molding panels larger than 1 m2 often is difficult, whereas thermoforming of large parts is proven and economical. Such parts are common on trucks, recreational vehicles, buses, and boats, all applications where metal and thermoset composites are widely used but etps are rare.
In automotive, trends that may support greater thermoforming of etps include the shift towards smaller production runs for more car models, which will lead suppliers to avoid costly injection molds for some parts. In markets such as marine, recreational vehicles, buses, and trucks, there is an ongoing transition from metal to plastics, as well as to stricter rules limiting voc emissions, which can affect composites use.
Still, etps are not inexpensive, which is one reason they are expected to be best received as contributors to multilayer sheet. There, they can offer improved esthetics, mechanical properties, and heat and chemical resistance at competitive systems costs with lower-price materials. “Thermoforming allows esthetics in applications where you would get flow lines or other problems in molded parts,” Murner says. “We see opportunities at the lower end, replacing abs, but also at the high end.”
Sowle says processor Spartech Plastics, St. Louis, mo, already is using the relatively expensive Geloy asa as the capstock layer of a 3-layer sheet with abs that is thermoformed and replaces a painted abs part. “The multilayer product has lower systems costs because there is no painting,” he notes.
Although materials development is ongoing, both Murner and Sowle reckon GEP already has many of the grades on hand — Noryl PPX polyphenylene oxide/polypropylene alloys, Lexan pc, Cycoloy pc/abs, and Geloy — albeit underutilized in thermoforming. “We’re enhancing [materials] where needed, but we think that with 30-plus extrusion grades we can meet many applications,” says Sowle. He adds that the supplier has proven the recyclability of its materials, an important criterion for sheet extrusion and thermoforming because the processes create more scrap than injection molding.
GEP is not the only etp supplier taking a close look at thermoforming. Solvay Engineered Polymers, Auburn Hills, mi, and Bayer, Leverkusen, Germany, have indicated their interest in getting their materials into more thermoforming applications. For thermoformers of technical parts, the attention may be late in coming, but it should prove worth the wait.